https://ej-eng.org/index.php/ejeng/issue/feed European Journal of Engineering and Technology Research 2025-02-11T21:16:42+01:00 Editor-in-Chief editor@ej-eng.org Open Journal Systems European Journal of Engineering and Technology Research https://ej-eng.org/index.php/ejeng/article/view/3217 On the Wavelength and Frequency of the Actual Chladni Patterns Visualized on Square Plates 2024-10-25T23:11:08+02:00 Barenten Suciu suciu@fit.ac.jp Sota Karimine mcm23101@bene.fit.ac.jp Naofumi Yamazumi s21e2070@bene.fit.ac.jp Yuki Mitsuishi s19e2054@bene.fit.ac.jp <p class="p1">In this study, Chladni patterns are visualized on square plates made of various metallic materials in the domain of low frequencies around the first flexural resonant peak. Using the membrane and the thin plate models, the undamped and damped natural frequency of the square panel is explicitly expressed versus the mean wavelength of the bending vibration. The wavelength of the idealized Chladni figures is evaluated for linear and curvilinear nodal lines relevant to our experiments. Significant discrepancy between the computed and measured frequencies is corrected based on the wavelength evaluation of the actual Chladni figures, done by considering the cutting and rounding of the nodal lines near the plate edges and near the central point of excitation. Such model able to link the shape of the actual nodal lines with the excitation frequency is useful for the motion control of micro-particles on the vibrating plate.</p> 2025-01-05T00:00:00+01:00 Copyright (c) 2025 Barenten Suciu, Sota Karimine, Naofumi Yamazumi, Yuki Mitsuishi https://ej-eng.org/index.php/ejeng/article/view/3206 Behavior of Anticorrosive Efficiency of Conventional Concrete Reinforced with Stainless Steel in the Presence of 5% CaCl2 2025-01-09T21:13:53+01:00 Brenda Paola Baltazar-García pao.baltazar.08@gmail.com Laura Landa-Ruiz lalanda@uv.mx Rene Croche aldlanda@uv.mx David Lozano dlozano@uv.mx José Reyes albreyes@uv.mx Gabriel Santos gasantos@uv.mx Ce Tochtli Méndez cmendez@uv.mx Francisco Estupiñan francisco.estupinan@uanl.edu.mx Citlalli Gaona citlalli.gaonatbr@uanl.edu.mx Miguel Angel Baltazar-Zamora mbaltazar@uv.mx <p class="p1">This project evaluated the behavior of the electrochemical corrosion resistance of AISI 304 Stainless Steel as reinforcement in conventional concrete, elaborated based on the method ACI 211.1, with a water/cement = 0.65 ratio. The samples were in the presence of water and a 5% CaCl<sub><span class="s1">2 </span></sub>solution for more than 160 days, the first environment representing a control medium and the second representing an aggressive medium. On the other hand, the electrochemical technique of linear polarisation resistance (Rp) was implemented for the determination of the intensity of corrosion current I<sub><span class="s1">corr </span></sub>and the measure of corrosion potencial E<span class="s1">corr</span>, in accordance with the ASTM C-876-15 method. As a result, E<sub><span class="s1">corr </span></sub>and I<span class="s1">corr </span>values were obtained, demonstrating a better performance against corrosion in the presence of a high level of chlorides when using AISI 304 Stainless Steel.</p> 2025-01-06T00:00:00+01:00 Copyright (c) 2025 Brenda Paola Baltazar-García, Laura Landa-Ruiz, Rene Croche, David Lozano, José Reyes, Gabriel Santos, Ce Tochtli Méndez, Francisco Estupiñan, Citlalli Gaona, Miguel Angel Baltazar-Zamora https://ej-eng.org/index.php/ejeng/article/view/3225 Blue-Shifting Photoluminescence in HFCVD-Deposited Tin-Doped SRO Films 2025-02-06T21:17:12+01:00 Daniel Diaz Tapia daniel.diazta@alumno.buap.mx Crisoforo Morales Ruiz crisomr@yahoo.com.mx Reina Galeazzi Isasmendi ingquim25@gmail.com Héctor Pérez Ladrón de Guevara hpldg@yahoo.com.mx Roberto Portillo portilloreyes@yahoo.com Roman Romano Trujillo roman.romano@correo.buap.mx Antonio Coyopol acoyopol@gmail.com Enrique Rosendo enrique171204@gmail.com <p class="p1">Silicon-rich oxide (SRO) films doped with tin (Sn-SRO) were successfully deposited using hot filament chemical vapor deposition (HFCVD), with tin-doped SBA-15 as the solid source material. SBA-15 acted as a protective layer, ensuring thermal stability and enabling the controlled incorporation of tin into the SRO films. Structural and optical analyses, including Fourier- transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), and photoluminescence (PL), were performed to evaluate the films. FTIR revealed SiO<span class="s1">2 </span>absorption peaks and Si-O-Sn bond formation, confirming the progressive incorporation of tin. TEM demonstrated the formation of silicon nanocrystals (Si-NCs), with decreasing size as tin concentration increased. This size reduction was correlated with enhanced PL intensity and a blue shift, attributed to stronger quantum confinement effects. These analyses provide a comprehensive understanding of the structural and optical behavior of Sn-doped SRO films. These findings highlight the potential of Sn-SRO films for optoelectronic applications, where controlling light emission and crystallinity is essential.</p> 2025-01-30T00:00:00+01:00 Copyright (c) 2025 Daniel Diaz Tapia, Crisoforo Morales Ruiz, Reina Galeazzi Isasmendi, Héctor Pérez Ladrón de Guevara, Roberto Portillo, Roman Romano Trujillo, Antonio Coyopol, Enrique Rosendo https://ej-eng.org/index.php/ejeng/article/view/3210 Construction of Machines Capable of Extracting Energy from the Forces of Nature with Over-unity Efficiencies is Made Possible 2025-02-11T21:16:42+01:00 Suniti Kumar Ghoshal sunitikghoshal@gmail.com <p class="p1">The possibility of constructing machines capable of extracting energy from the forces of nature with N &gt; 1 efficiencies by making use of novel energy-harvesting ideas has been brought to light. The electrostatic, magnetic and electromagnetic forces have been identified as the promising ones to meet this objective. The working of one of such machines is based on the simple idea of allowing both the charging and discharging currents of a capacitor to pass through a DC motor uni-directionally repetitively. The second kind of machine, capable of extracting energy from magnetic forces, makes use of both attractive and repulsive forces between pole pieces of permanent and electromagnets. This machine is capable of generating energy with N &gt; 1 efficiencies as it effectively extracts energy from both the attractive and repulsive magnetic forces. The machines of the third kind take advantage of Barlow’s motor, which, when connected in series with a DC motor and a DC current is passed through them the Barlow’s motor generates energy without the consumption of any electrical power. The possible ways of improving the efficiency of the machines are discussed.</p> 2025-01-17T00:00:00+01:00 Copyright (c) 2025 Suniti Kumar Ghoshal